The problem of spending loads of time separating each plant ( all seedlings) from their trays and then replanting them spaced apart, I like to think has been avoided ,by running a plastic cake spatula round the edge of each tray and then tossing each whole tray out into a slight depression in the raised beds.
Backfiling with soil, and then using the tray to safely, protect from birds etc , slug pellets, then a wire peg holds the tray from blowing away.
Providing plants have made good root growth in their tray they come out very easily.
This took about one and a half hours to complete.
With seedlings perhaps 99% will be discarded as not being an improvement on names Florist types and also wide planting tend to ensure lots of leaf ,but little flower at the start of the season.
So quicker production of flowers and quicker identification of those worth keeping is ensured with this method.
Any worthwhile saving will be dug up and potted on for cuttings or cross breeding this year.
The best laid plans of mice and men comes to mind !!!!!